For the scripts, under General... you can assign shortcuts to "run script number #". Other than that. I don't think you can add a shortcut when there is none.

I sometime ago wanted to add a shortcut to the "invert keyframes" command. The way I could get it to work was a script that executed that command and adding a shortcut to it. All you got to do is rename your scripts accordingly so they won't change hierarchy when you add more to the scripts folder.